1. Introduction
Plant tissue culture media are built from a blend of inorganic salts, organic compounds, and optional supplements. Different formulations are used depending on the species being cultured and the desired outcome (e.g., callus formation, rooting, shoot multiplication).
All media contain:
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Macronutrients and micronutrients
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Vitamins and sugar
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Growth regulators (optional)
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Gelling agent (for solid/semi-solid media)
2. Common Media Formulations
| Medium | Use | Features |
|---|---|---|
| MS Medium | Most common across species | High nitrogen, good for shoot and root development |
| B5 Medium | Protoplasts, cell suspensions | Lower nitrogen, good for cell cultures |
| White’s Medium | Root and organ cultures | One of the earliest synthetic media |
| WPM | Woody plants | Reduced salt for delicate tissues |
You can also modify these media by adjusting:
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Macronutrient ratios
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Sugar concentrations
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PGR levels
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Solid vs. liquid format
📌 WPM and Woody Species Reference
3. Macronutrients and Micronutrients
Plants require 17 essential nutrients; most are included in culture media.
Macronutrients:
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N, P, K – Primary nutrients needed for structural growth
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Ca, Mg, S – Secondary nutrients important for enzyme function and structure
Micronutrients:
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Fe, Mn, Zn, Cu, B, Mo
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Present in trace amounts but vital for chloroplast development, redox balance, and DNA synthesis
📌 Plant Nutrition and In Vitro Culture
4. Organic Nutrients
| Component | Function |
|---|---|
| Sucrose | Energy source for growing tissues |
| Thiamine (B1) | Essential cofactor in metabolism |
| Nicotinic Acid (B3) | Redox reactions |
| Pyridoxine (B6) | Amino acid metabolism |
| Glycine, Casein Hydrolysate | Boost callus and root growth |
Sucrose is the most common sugar added—glucose and fructose are used in special cases.
5. Gelling and Additives
Agar is used to solidify media, allowing tissue to stay upright and form callus or roots.
Alternatives:
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Gelrite or Phytagel: Higher purity, clearer, useful for photography or microscopy
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Activated Charcoal: Used in media for orchids, bananas, or woody species to adsorb toxins and reduce browning
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Additives like banana or coconut water may provide natural PGRs and carbohydrates, especially in traditional protocols